Root Fracture Resistance of Maxillary Premolars Obturated with Three Root Canal Sealers after Passive Utrasonic Irrigation: An in Vitro study.

Introduction: Maxillary premolars, may be more susceptible to fracture due to their anatomy; especially when there is loss of tooth structure. Therefore, it is necessary to evaluate materials and techniques that may increase fracture resistance during and post root canal treatment. This in vitro study aimed to evaluate root fracture resistance of maxillary premolars when filled with three root canal sealers as well as whether this resistance would be increased by passive ultrasonic irrigation (PUI). Methods and Materials: Sixty-four maxillary premolars with two roots were randomly divided into one negative control group (intact canals; n = 8), one positive control group (instrumented, unsealed canals; n = 8), and six experimental groups (n = 8), which were instrumented with ProTaper Next rotary system up to X2 file and subdivided according to final irrigation (with or without PUI) and type of sealer used (AH-Plus [AH], MTA Fillapex [MTA], or EndoSequence BC Sealer [ES]). The specimens were subjected to fracture strength test in a universal testing machine at a speed of 1 mm/min until fracture. The maximum force required to induce fracture was recorded (N). The Kruskal-Wallis test and DUNN test were used for analysis. Results: The lowest force required to cause root fracture was observed in the positive control group (310.48 ± 54.08 N); this was significantly different from the other groups (P < 0.05). There was no significant difference between experimental groups obturated with the same sealer, whether with or without PUI (AH with PUI: 558.80 ± 87.12 N; AH without PUI: 508.75 ± 97.55 N; MTA with PUI: 507.27 ± 174.55 N; MTA without PUI: 516.69 ± 96.56 N; ES with PUI: 526.76 ± 143.97 N; ES without PUI: 628.40 ± 94.74 N) (P > 0.05). There was also no significant difference between the experimental groups and the negative control group (P > 0.05). Conclusions: In this in vitro study PUI did not increase the fracture resistance of maxillary premolars, while AH Plus, MTA Fillapex, EndoSequence sealers increased fracture resistance of instrumented root canals.

Avaliação da radiopacidade de cimentos endodônticos através de radiografias digitais / Evaluation of radiopacity of endodontic cements using digital X-ray

A radiopacidade ‚ uma das propriedades essenciais dos cimentos obturadores endodônticos, pois permite ao profissional avaliar a qualidade da obturação de canais radiculares e, consequentemente, a previsibilidade do tratamento. As especificações de radiopacidade foram avaliadas de acordo com a norma ISO 6876/2001. Para a análise da radiopacidade, 10 placas acrílicas foram confeccionadas com seis cavidades, cada uma com 5,0 mm de diâmetro e 2,0 mm de espessura e preenchidas com os cinco cimentos estudados: AHPlus, Endofill, Fill Canal, Sealapex, Sealer 26 e, como controle, foi utilizada guta-percha. Imagens radiográficas digitais dos espécimes foram importadas do software Digora for Windows versão 1.51. Uma escala de alumínio foi utilizada como um instrumento de medição da densidade radiográfica na comparação das amostras, e o valor da radiopacidade foi determinado de acordo com essa densidade radiográfica (mm Al). Os resultados foram analisados estatisticamente por teste ANOVA e complementados por Tukey. Os cimentos testados apresentaram diferenças estatisticamente significantes entre eles (p<0,005). Os valores da radiopacidade dos cimentos em ordem decrescente foram os seguintes: AHPlus (13,456ñ 0,069); Sealer 26 (11,197ñ0,039); Endofill (11,050ñ0,016); Fill Canal (9,793ñ0,074) e Sealapex (7,604ñ0,057). A radiopacidade da guta-percha (10,912ñ0,054) foi menor que o AHPlus, Sealer 26 e Endofill, por‚m todos os materiais testados preencheram os requisitos das normas ISO 6876/2001

Radiopacity is an essential attribute of endodontic filling materials because it allows an evaluation of the root canal filling, and thus the predictability of the treatment. Radiopacity was evaluated according to ISO 6876/2001 standards. For radiopacity analysis, ten acrylic plates were made, each with six holes 10.0 mm diameter and 2.0 mm thickness which were filled with the five studied cements: AHPlus, Endofill, Fill Canal, Sealapex, Sealer 26 and, as control was used guta-percha. Digital radiographic images of the patients were imported into the software Digora for Windows version 1.51. An aluminum step wedge was used to measure the radiographic density in the comparison of the samples. The radiopacity value was determined according to radiographic density (mm Al). The studied cements have presented statistically significant differences among them (p<0.005). Radiopacity values of the cements in descending order were: AHPlus (13.456ñ0.069); Sealer 26 (11.197ñ0.039); Endofill (11,050ñ0,016); FillCanal (9,793ñ0,074); and Sealapex (7.604ñ0.057). The radiopacity of guta-percha (10.912ñ0.054) was lower than AHPlus, Sealer 26 and Endofill, however all the tested materials were in accordance with the ISO 6876 normative

Location of three canals in the mesiobuccal root of the maxillary first molar

Introduction:The knowledge on the complex anatomy of the maxillary first molar and location of extra canals are essential for diagnosis and endodontic treatment success. Objective:The purpose of this study was to report a clinical case showing a varied number of root canals in maxillary molars with the aid of the operating microscope (OM). Case report: The endodontic retreatment of the right maxillary first molar with unusual anatomical variation was performed, displaying three canals in the mesiobuccal root (MB), a root canal in the distobuccal root (DV) and a root canal in the palatal root (P). To remove the resin core inside pulp chamber with and without the aid of dental operating microscope, a high-speed drill and ultrasonic tip (diamond round) was used, respectively, for the refinement of the pulp chamber walls. The dental operating microscopewas used during the access surgery, location, negotiation of canals and checking of the completion of all stages of the retreatment. Subsequently, the cleaning, shaping and filling of the root canal system was completed. The presence of three canals in the mesiobuccal root, one in the distobuccal root and one in the palatal root was found. Conclusion: Variations in the number of canals could be confirmed during the surgery access in endodontic retreatment cases with the aid of dental operating microscope.